ft90x uvc webcam - ftdi · application note an_414 ft90x uvc webcam version 1.1 document reference...

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Application Note

AN_414

FT90x UVC WebCam

Version 1.1

Issue Date: 2017-02-17

This application note describes using the camera interface on the FT90x to create a UVC compliant webcam USB device.

http://brtchip.com/

Application Note

AN_414 FT90x UVC WebCam Version 1.1

Document Reference No.: BRT_000103 Clearance No.: BRT#061

1 Product Page

Document Feedback Copyright © Bridgetek Limited

Table of Contents

1 Introduction .............................................................. 3

1.1 Overview ............................................................................. 3

1.2 Scope .................................................................................. 3

1.2.1 Features ............................................................................................ 3

1.2.2 Enhancement ..................................................................................... 4

2 Project Overview ....................................................... 5

2.1 Main Program ...................................................................... 5

2.2 Camera Control ................................................................... 5

2.3 Camera Interface ................................................................ 5

2.3.1 I2C Master Interface ............................................................................ 6

2.3.2 GPIO Handler ..................................................................................... 6

2.4 USB Interface ...................................................................... 6

2.5 Power Management Handler ............................................... 6

2.6 Other Features .................................................................... 6

3 Code Structure........................................................... 7

4 USB Configuration ................................................... 10

4.1 High-speed Configuration Descriptor ................................ 10

4.2 Full-speed Configuration ................................................... 17

5 Testing .................................................................... 18

5.1 VLC Media Player ............................................................... 18

5.2 Skype ................................................................................ 20

5.3 Windows 10 Camera App ................................................... 20

6 Performance ............................................................ 21

7 Importing into the FT90x Toolchain ........................ 22

7.1 Changing the Application Software ................................... 22

8 Contact Information ................................................ 23

Appendix A – References ............................................. 24

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mailto:[email protected]?subject=Document%20Feedback:%20AN_414%20Version%201.1

Application Note



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Document References ............................................................... 24

Acronyms and Abbreviations ..................................................... 24

Appendix B – List of Tables & Figures .......................... 25

List of Tables ............................................................................. 25

List of Figures ........................................................................... 25

Appendix C – Revision History ..................................... 26



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1 Introduction

The FT900/FT901 and FT905/FT906 devices include a Camera Interface and Serial Camera Control Bus (SCCB - implemented as an I2C Master on the FT90x). This can be used with suitable USB code to implement a UVC webcam.

This application note demonstrates how data from the camera interface can be read and sent to the USB interface. A USB host can receive the video data and display the output as it would with a dedicated webcam.

1.1 Overview

The source of the video data is the camera interface. This receives data streamed from a camera module on an 8-bit parallel bus. This is buffered in the camera interface peripheral and an

interrupt signals to the CPU that data is available. Data can then be read into memory by an

application.

Because of the high throughput of data, special features of the FT90x core are used. The interrupt routine uses the “streaming” instruction to transfer data from the camera interface registers to memory as fast as possible.

Support is provided for two camera modules, the OV9657 and OV5640. Both modules can output an uncompressed YUY2 stream; the OV5640 can also output a compressed Motion JPEG (MJPEG)

stream.

The UVC device has configurations for hi-speed and full-speed devices, however data will only be transferred if the device enumerates as a hi-speed device. This implementation, by default, will allow QVGA and VGA resolutions (320x240, 640x480 respectively) uncompressed at high-speed, and additionally at SVGA resolution (800x600) in MJPEG format. All are at 15 frames per second.

Data is transferred to the USB host using either bulk transfers or isochronous transfers. By default, a bulk endpoint is used to transfer data rather than the more common isochronous endpoint. This

can be changed in the code. When using isochronous transfers only QVGA is supported.

1.2 Scope

The webcam application demonstrates the creation of a UVC compatible USB device which will

stream video data to a USB host. It does not include audio. Either uncompressed data or MJPEG can be sent to the host. The format of both types of data stream is not altered by the application and is dependent on the camera module sending correctly formatted data.

This is a minimum implementation of the UVC class protocol. In hi-speed mode there is up-to 2 formats allowed and support for up-to 5 resolutions. The available formats and resolutions depend on the camera module used. There are no video streaming interfaces at full-speed. USB device endpoint types of bulk and isochronous are shown. Camera module type, formats, resolutions and

endpoint type are configured as build options.

The UVC device is coded to support UVC revision 1.1 to allow for a wide range of USB hosts to work with the webcam.

1.2.1 Features

This application features methods to receive data from the camera interface as fast as possible and

for efficiently sending that data to the USB host.

The FT90x features shown are:

Providing a USB device with configuration descriptors for composite devices, containing interface association descriptors and supporting multiple interfaces and endpoints.

Sending partial packets of data to the USB device using multiple calls to USBD_transfer_ex() function.

Using the “streaming” instruction to access a peripheral register.



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Accessing the camera interface. Using 16-bit addressing on the I2C master interface.

1.2.2 Enhancement

Enhancements to this application might be:

To implement variable frame rates. Add audio channel. Improve feedback to the host on changes in gain.

This UVC webcam example application should be treated as an example. Full source code is provided allowing users to build and modify if required:

http://brtchip.com/wp-content/uploads/FT90x/AN_414_FT90x_UVC_Webcam.zip




Application Note



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2 Project Overview

The project files for this application note are divided into the following folders.

Folder Description

Source Application source code and camera module

specific files.

Lib Library files.

lib\tinyprintf tinyprintf library.

Table 2.1 Project Files Overview

The application source code is contained within the “Sources” folder. The main() function and the

high-level functions of the application are in the “main.c” file. In this folder there are camera

module specific file for each supported camera module.

2.1 Main Program

The main program is responsible for setting up the hardware and handling data between the camera interface and the USB device.

The main() function performs hardware setup for the camera interface, I2C master (for the SCCB), GPIO, timers, UART (for debug output) and power management.

Once the hardware is setup then the usbd_testing() function is called which receives USB requests, UVC device state changes and performs the streaming of data from the camera interface to the USB.

2.2 Camera Control

The camera module requires initialization and some control functions to allow it to be set to stream video data in the correct format. The functions for this are contained in separate files to allow changes to the supported camera modules.

At present the OmniVision OV9657 and OV5640 camera modules are supported and the required functions are included in the files “ov965x_camera.c” and “ov5640_camera.c” respectively.

These files implement an initialization function (mapped to camera_init), a setup function

(camera_set), a start streaming function (camera_start) and a stop streaming function

(camera_stop).

Preprocessor macros are used to map the required functions to module-specific functions in the module source files.

The setup function is responsible for configuring the camera module in the correct

2.3 Camera Interface

An interrupt handler is started when data is available from the camera interface. This handler streams a line of video data at a time to the main memory. An array capable of holding data from several lines of video is used to allow several lines of data to be buffered.

The interrupt handler will detect the end of a frame and wait for a frame synchronization signal from the camera module which is received on a GPIO line.



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2.3.1 I2C Master Interface

The camera module is controlled by commands to read and write registers on an SCCB which is implemented as an I2C master bus. This is camera module specific.

The FT90x library driver for I2C only supports 8-bit addressing. The OV5640 module code includes a set of subroutines to allow 16-bit addressing on the I2C bus. These may be reused for other projects.

2.3.2 GPIO Handler

One GPIO input is configured to receive a frame synchronization signal from the camera module.

This is used by the camera interface interrupt handler to signal the start of a new frame of video.

2.4 USB Interface

A handler has been implemented for UVC class requests. Only class requests used by the Windows

USB video device driver are implemented.

Configuration descriptors are provided for hi-speed and full-speed operation. The UVC video configuration descriptors are included. These describe the capabilities and video formats used by the UVC interface.

There is an option to use bulk or isochronous data endpoints. A macro “USB_ENDPOINT_USE_ISOC” should be defined to enable isochronous otherwise bulk will be used. The data rate available from bulk data endpoints is higher and will therefore support higher

resolutions. When isochronous data endpoints are enabled the SetInterface request is used to enable data transmission over the USB.

Class-specific configuration settings are defined for use by the GET_CUR, GET_MIN, GET_MAX, GET_DEF, GET_RES and SET_CUR requests.

2.5 Power Management Handler

When moving between suspend and resume states on USB, the power management handler is required to notify the USBD (USB device) library that the bus state has changed.

2.6 Other Features

The DFU-C facility may be enabled for this application. It can be enabled at startup or can provide a separate interface for updating.

To enable the DFU at startup define the USB_INTERFACE_USE_STARTUPDFU macro. This enables a call

from the macro STARTUP_DFU() in the main() function. It will briefly enable the USB device on the FT90x and allow a DFU utility to update the application code. This can be removed entirely or

configured to alter the number of milliseconds it will wait before closing the USB device and continuing with the application.

To have a DFU interface during normal operation define the USB_INTERFACE_USE_DFU macro.



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3 Code Structure

The code is written to send data from the camera interface to the USB library efficiently.

Interrupt handlers receive data from the camera interface after synchronising with the vertical sync signal from the camera module (Figure 3.1).

The main function “usbd_testing()” polls flags from the camera interrupt handler and sends any

data received from the camera interface to the USB device interface (Figure 3.2).

An efficient method of sending data to the USB interface is used. The number of times data is

copied is minimised in both the interrupt handler and the main code. Although the FT90x has efficient and fast “memcpy” instructions implemented in silicon it is still faster to avoid copying data.

The initial stream of data from the camera interface is sent to a memory buffer which can hold several lines of video data. It is copied directly from this buffer into the USB transmit buffer when required. The USBD_transfer_ex() function allows a USB packet to be built up with one or more

calls to the function being used to prepend the UVC Payload Header structure to the video data.

When the USBD_transfer_ex() function is called, setting the “flags” parameter will prevent the

function from sending the data. It will wait for further calls to the function to allow the transmit buffer to be loaded. Once it is called with the flags parameter clear then it will send the data in the buffer, however, if the buffer fills to the endpoint maximum packet size then the data will be transmitted. The USB protocol, when using a bulk endpoint, will assume that this is part of a longer transfer. The “offset” parameter is used to ensure that data is sent on the endpoint

maximum packet size boundary correctly.

Since this feature is used, the UVC payload header can be made separately from the camera interface buffer avoiding the need to copy data before transmission.

The camera interface data is buffered to allow the USB transmission to “catch up”. There is a gap between frames and data remaining in the buffer may be sent in this time. If data from a new frame is received before the USB side has finished then the USB frame will restart with the new

data.

When discussing “lines” of data in this application, an uncompressed line of data is defined as the

data stream which includes one complete line (horizontal resolution * bytes per pixel); a compressed line is a configurable length of data of which multiple lines make up a compressed frame.



Application Note



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Figure 3.1 Camera Interface Flowchart

Frame detection is handled in the main code rather than the interrupt handler. The camera module is configured to send a fixed amount of data per frame (for both uncompressed and MJPEG frames).

For uncompressed data the frame detection code counts the number of lines received from the

camera module and signals a frame end when the number of lines received reaches the expected lines in the frame.

For compressed MJPEG data the frame detection code parses the data stream for JPEG markers which indicate the start and end of each frame.

cam_ISR()

Interrupt handler.

Increment

number of lines available counter

vertical sync?

Clear

Stream line of data into buffer.

Enough

data for a video line?

Set

vsync_ISR()

Interrupt handler.

Set vertical sync flag.

Yes

No



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Figure 3.2 Main Control Flowchart

usbd_testing ()

Initialise USB device

UVC active?

No

No

Handle USB events

USBD_Process()

camera change?

Start/stop camera

data from camera?

start of frame?

Toggle frame ID bit.

Set end of frame flag in payload header.

Reset buffer pointers.

end of frame?

start of line?

Send packet of data to USB.

Make payload header. Send to USB.

No

No

No

Yes Yes

Yes

Yes

Yes

No

Yes



Application Note



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4 USB Configuration

4.1 High-speed Configuration Descriptor

The following configuration descriptor is taken from the FT90x device by “USBview” from Microsoft. It is based on the configuration where:

The camera module is an OV5640, MJPEG streaming is enabled supporting QVGA (default), VGA and SVGA. Uncompressed streaming is enabled supporting QVGA (default) and VGA. A bulk endpoint is used for streaming.

---===>Device Information<===--- English product name: "FT900 UVC" ConnectionStatus: Current Config Value: 0x01 -> Device Bus Speed: High Device Address: 0x02 Open Pipes: 2 ===>Device Descriptor<=== bLength: 0x12 bDescriptorType: 0x01 bcdUSB: 0x0200 bDeviceClass: 0xEF -> This is a Multi-interface Function Code Device bDeviceSubClass: 0x02 -> This is the Common Class Sub Class bDeviceProtocol: 0x01 -> This is the Interface Association Descriptor protocol bMaxPacketSize0: 0x40 = (64) Bytes idVendor: 0x0403 = Future Technology Devices International Limited idProduct: 0x0FD8 bcdDevice: 0x0101 iManufacturer: 0x01 English (United States) "FTDI" iProduct: 0x02 English (United States) "FT900 UVC" iSerialNumber: 0x03 English (United States) "FT424242" bNumConfigurations: 0x01 ---===>Open Pipes<===--- ===>Endpoint Descriptor<=== bLength: 0x07 bDescriptorType: 0x05 bEndpointAddress: 0x81 -> Direction: IN - EndpointID: 1 bmAttributes: 0x03 -> Interrupt Transfer Type wMaxPacketSize: 0x0040 = 1 transactions per microframe, 0x40 max bytes bInterval: 0x08 ===>Endpoint Descriptor<=== bLength: 0x07 bDescriptorType: 0x05 bEndpointAddress: 0x82 -> Direction: IN - EndpointID: 2 bmAttributes: 0x02 -> Bulk Transfer Type wMaxPacketSize: 0x0200 = 0x200 max bytes bInterval: 0x00



http://www.ftdichip.com/Support/Utilities.htm#MicrosoftUSBView

Application Note



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---===>Full Configuration Descriptor<===--- ===>Configuration Descriptor<=== bLength: 0x09 bDescriptorType: 0x02 wTotalLength: 0x0180 -> Validated bNumInterfaces: 0x03 bConfigurationValue: 0x01 iConfiguration: 0x00 bmAttributes: 0x80 -> Bus Powered MaxPower: 0xFA = 500 mA ===>IAD Descriptor<=== bLength: 0x08 bDescriptorType: 0x0B bFirstInterface: 0x00 bInterfaceCount: 0x02 bFunctionClass: 0x0E -> Video Interface Class bFunctionSubClass: 0x03 -> Video Interface Collection bFunctionProtocol: 0x00 -> PC_PROTOCOL_UNDEFINED protocol iFunction: 0x02 English (United States) "FT900 UVC" ===>Interface Descriptor<=== bLength: 0x09 bDescriptorType: 0x04 bInterfaceNumber: 0x00 bAlternateSetting: 0x00 bNumEndpoints: 0x01 bInterfaceClass: 0x0E -> Video Interface Class bInterfaceSubClass: 0x01 -> Video Control Interface SubClass bInterfaceProtocol: 0x00 iInterface: 0x02 English (United States) "FT900 UVC" ===>Class-Specific Video Control Interface Header Descriptor<=== bLength: 0x0D bDescriptorType: 0x24 bDescriptorSubtype: 0x01 bcdUVC: 0x0110 wTotalLength: 0x0043 -> Validated dwClockFreq: 0x02DC6C00 = (48000000) Hz bInCollection: 0x01 baInterfaceNr[1]: 0x01 USB Video Class device: spec version 1.1 ===>Video Control Input Terminal Descriptor<=== bLength: 0x11 bDescriptorType: 0x24 bDescriptorSubtype: 0x02 bTerminalID: 0x01 wTerminalType: 0x0201 = (ITT_CAMERA) bAssocTerminal: 0x00 iTerminal: 0x00 ===>Camera Input Terminal Data wObjectiveFocalLengthMin: 0x0000 wObjectiveFocalLengthMax: 0x0000 wOcularFocalLength: 0x0000 bControlSize: 0x02 bmControls : 0x00 0x00 D00 = 0 no - Scanning Mode D01 = 0 no - Auto-Exposure Mode D02 = 0 no - Auto-Exposure Priority



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D03 = 0 no - Exposure Time (Absolute) D04 = 0 no - Exposure Time (Relative) D05 = 0 no - Focus (Absolute) D06 = 0 no - Focus (Relative) D07 = 0 no - Iris (Absolute) D08 = 0 no - Iris (Relative) D09 = 0 no - Zoom (Absolute) D10 = 0 no - Zoom (Relative) D11 = 0 no - PanTilt (Absolute) D12 = 0 no - PanTilt (Relative) D13 = 0 no - Roll (Absolute) D14 = 0 no - Roll (Relative) D15 = 0 no - Reserved ===>Video Control Input Terminal Descriptor<=== bLength: 0x08 bDescriptorType: 0x24 bDescriptorSubtype: 0x02 bTerminalID: 0x02 wTerminalType: 0x0200 = (ITT_VENDOR_SPECIFIC) bAssocTerminal: 0x00 iTerminal: 0x00 ===>Video Control Output Terminal Descriptor<=== bLength: 0x09 bDescriptorType: 0x24 bDescriptorSubtype: 0x03 bTerminalID: 0x03 wTerminalType: 0x0101 = (TT_STREAMING) bAssocTerminal: 0x00 bSourceID: 0x05 iTerminal: 0x00 ===>Video Control Selector Unit Descriptor<=== bLength: 0x08 bDescriptorType: 0x24 bDescriptorSubtype: 0x04 bUnitID: 0x04 bNrInPins: 0x02 ===>List of Connected Unit and Terminal ID's baSourceID[1]: 0x01 baSourceID[2]: 0x02 iSelector: 0x00 ===>Video Control Processing Unit Descriptor<=== bLength: 0x0C bDescriptorType: 0x24 bDescriptorSubtype: 0x05 bUnitID: 0x05 bSourceID: 0x04 wMaxMultiplier: 0x0000 bControlSize: 0x02 bmControls : 0x00 0x00 D00 = 0 no - Brightness D01 = 0 no - Contrast D02 = 0 no - Hue D03 = 0 no - Saturation D04 = 0 no - Sharpness D05 = 0 no - Gamma D06 = 0 no - White Balance Temperature D07 = 0 no - White Balance Component D08 = 0 no - Backlight Compensation D09 = 0 no - Gain



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D10 = 0 no - Power Line Frequency D11 = 0 no - Hue, Auto D12 = 0 no - White Balance Temperature, Auto D13 = 0 no - White Balance Component, Auto D14 = 0 no - Digital Multiplier D15 = 0 no - Digital Multiplier Limit iProcessing : 0x00 bmVideoStandards : 0x00 D00 = 0 no - None D01 = 0 no - NTSC - 525/60 D02 = 0 no - PAL - 625/50 D03 = 0 no - SECAM - 625/50 D04 = 0 no - NTSC - 625/50 D05 = 0 no - PAL - 525/60 D06 = 0 no - Reserved D07 = 0 no - Reserved ===>Endpoint Descriptor<=== bLength: 0x07 bDescriptorType: 0x05 bEndpointAddress: 0x81 -> Direction: IN - EndpointID: 1 bmAttributes: 0x03 -> Interrupt Transfer Type wMaxPacketSize: 0x0040 = 1 transactions per microframe, 0x40 max bytes bInterval: 0x08 ===>Class-specific VC Interrupt Endpoint Descriptor<=== bLength: 0x05 bDescriptorType: 0x25 bDescriptorSubtype: 0x03 wMaxTransferSize: 0x0040 = (64) Bytes ===>Interface Descriptor<=== bLength: 0x09 bDescriptorType: 0x04 bInterfaceNumber: 0x01 bAlternateSetting: 0x00 bNumEndpoints: 0x01 bInterfaceClass: 0x0E -> Video Interface Class bInterfaceSubClass: 0x02 -> Video Streaming Interface SubClass bInterfaceProtocol: 0x00 iInterface: 0x00 ===>Video Class-Specific VS Video Input Header Descriptor<=== bLength: 0x0F bDescriptorType: 0x24 bDescriptorSubtype: 0x01 bNumFormats: 0x02 -> Uncompressed and MJPEG wTotalLength: 0x00F5 -> Validated bEndpointAddress: 0x82 -> Direction: IN - EndpointID: 2 bmInfo: 0x00 -> Dynamic Format Change not Supported bTerminalLink: 0x03 bStillCaptureMethod: 0x00 -> No Still Capture bTriggerSupport: 0x00 -> No Hardware Triggering Support bTriggerUsage: 0x00 bControlSize: 0x01 Video Payload Format 1 0x00 D00 = 0 no - Key Frame Rate D01 = 0 no - P Frame Rate D02 = 0 no - Compression Quality D03 = 0 no - Compression Window Size D04 = 0 no - Generate Key Frame D05 = 0 no - Update Frame Segment D06 = 0 no - Reserved



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D07 = 0 no - Reserved Video Payload Format 2 0x00 D00 = 0 no - Key Frame Rate D01 = 0 no - P Frame Rate D02 = 0 no - Compression Quality D03 = 0 no - Compression Window Size D04 = 0 no - Generate Key Frame D05 = 0 no - Update Frame Segment D06 = 0 no - Reserved D07 = 0 no - Reserved ===>Video Streaming Uncompressed Format Type Descriptor<=== bLength: 0x1B bDescriptorType: 0x24 bDescriptorSubtype: 0x04 bFormatIndex: 0x01 bNumFrameDescriptors: 0x02 guidFormat: {32595559-0000-0010-8000-00AA00389B71} = YUY2 Format bBitsPerPixel: 0x10 bDefaultFrameIndex: 0x01 bAspectRatioX: 0x04 bAspectRatioY: 0x03 bmInterlaceFlags: 0x00 D0 = 0x00 Interlaced stream or variable: No D1 = 0x00 Fields per frame: 2 fields D2 = 0x00 Field 1 first: No D3 = 0x00 Reserved D4..5 = 0x00 Field patterns -> Field 1 only D6..7 = 0x00 Display Mode -> Bob only bCopyProtect: 0x00 -> Duplication Unrestricted ===>Video Streaming Uncompressed Frame Type Descriptor<=== --->This is the Default (optimum) Frame index bLength: 0x1E bDescriptorType: 0x24 bDescriptorSubtype: 0x05 bFrameIndex: 0x01 bmCapabilities: 0x00 wWidth: 0x0140 = 320 wHeight: 0x00F0 = 240 dwMinBitRate: 0x02328000 dwMaxBitRate: 0x02328000 dwMaxVideoFrameBufferSize: 0x00025800 dwDefaultFrameInterval: 0x000A2C2A = 66.666600 mSec (15.00 Hz) bFrameIntervalType: 0x01 ===>Additional Discrete Frame Type Data dwFrameInterval[1]: 0x000A2C2A = 66.666600 mSec (15.00 Hz) ===>Video Streaming Uncompressed Frame Type Descriptor<=== bLength: 0x1E bDescriptorType: 0x24 bDescriptorSubtype: 0x05 bFrameIndex: 0x02 bmCapabilities: 0x00 wWidth: 0x0280 = 640 wHeight: 0x01E0 = 480 dwMinBitRate: 0x04650000 dwMaxBitRate: 0x04650000 dwMaxVideoFrameBufferSize: 0x00096000 dwDefaultFrameInterval: 0x000A2C2A = 66.666600 mSec (15.00 Hz) bFrameIntervalType: 0x01 ===>Additional Discrete Frame Type Data dwFrameInterval[1]: 0x000A2C2A = 66.666600 mSec (15.00 Hz)



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===>Color Matching Descriptor<=== bLength: 0x06 bDescriptorType: 0x24 bDescriptorSubtype: 0x0D bColorPrimaries: 0x01 bTransferCharacteristics: 0x01 bMatrixCoefficients: 0x04 ===>Video Streaming MJPEG Format Type Descriptor<=== bLength: 0x0B bDescriptorType: 0x24 bDescriptorSubtype: 0x06 bFormatIndex: 0x02 bNumFrameDescriptors: 0x04 bmFlags: 0x01 -> Sample Size is Fixed bDefaultFrameIndex: 0x01 bAspectRatioX: 0x04 bAspectRatioY: 0x03 *!*ERROR: bAspectRatioX and bAspectRatioY must be 0 if stream non-Interlaced bmInterlaceFlags: 0x00 D00 = 0 non-Interlaced stream or variable D01 = 0 2 fields per frame D02 = 0 Field 1 not first D03 = 0 Reserved D4..5 = 0 Field patterns -> Field 1 only D6..7 = 0 Display Mode -> Bob only bCopyProtect: 0x00 -> Duplication Unrestricted ===>Video Streaming MJPEG Frame Type Descriptor<=== --->This is the Default (optimum) Frame index bLength: 0x1E bDescriptorType: 0x24 bDescriptorSubtype: 0x07 bFrameIndex: 0x01 bmCapabilities: 0x00 wWidth: 0x0140 = 320 wHeight: 0x00F0 = 240 dwMinBitRate: 0x00119400 dwMaxBitRate: 0x00119400 dwMaxVideoFrameBufferSize: 0x000012C0 dwDefaultFrameInterval: 0x000A2C2A = 66.666600 mSec (15.00 Hz) bFrameIntervalType: 0x01 ===>Additional Discrete Frame TypeData dwFrameInterval[1]: 0x000A2C2A = 66.666600 mSec (15.00 Hz) ===>Video Streaming MJPEG Frame Type Descriptor<=== bLength: 0x1E bDescriptorType: 0x24 bDescriptorSubtype: 0x07 bFrameIndex: 0x02 bmCapabilities: 0x00 wWidth: 0x0280 = 640 wHeight: 0x01E0 = 480 dwMinBitRate: 0x001C2000 dwMaxBitRate: 0x001C2000 dwMaxVideoFrameBufferSize: 0x00003C00 dwDefaultFrameInterval: 0x000A2C2A = 66.666600 mSec (15.00 Hz) bFrameIntervalType: 0x01 ===>Additional Discrete Frame TypeData dwFrameInterval[1]: 0x000A2C2A = 66.666600 mSec (15.00 Hz) ===>Video Streaming MJPEG Frame Type Descriptor<===



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bLength: 0x1E bDescriptorType: 0x24 bDescriptorSubtype: 0x07 bFrameIndex: 0x03 bmCapabilities: 0x00 wWidth: 0x0320 = 800 wHeight: 0x0258 = 600 dwMinBitRate: 0x00232800 dwMaxBitRate: 0x00232800 dwMaxVideoFrameBufferSize: 0x00004B00 dwDefaultFrameInterval: 0x000A2C2A = 66.666600 mSec (15.00 Hz) bFrameIntervalType: 0x01 ===>Additional Discrete Frame TypeData dwFrameInterval[1]: 0x000A2C2A = 66.666600 mSec (15.00 Hz) ===>Video Streaming MJPEG Frame Type Descriptor<=== bLength: 0x1E bDescriptorType: 0x24 bDescriptorSubtype: 0x07 bFrameIndex: 0x04 bmCapabilities: 0x00 wWidth: 0x0400 = 1024 wHeight: 0x0300 = 768 dwMinBitRate: 0x00106800 dwMaxBitRate: 0x00106800 dwMaxVideoFrameBufferSize: 0x00004B00 dwDefaultFrameInterval: 0x00145855 = 133.333300 mSec (7.50 Hz) bFrameIntervalType: 0x01 ===>Additional Discrete Frame TypeData dwFrameInterval[1]: 0x00145855 = 133.333300 mSec (7.50 Hz) ===>Color Matching Descriptor<=== bLength: 0x06 bDescriptorType: 0x24 bDescriptorSubtype: 0x0D bColorPrimaries: 0x01 bTransferCharacteristics: 0x01 bMatrixCoefficients: 0x04 ===>Endpoint Descriptor<=== bLength: 0x07 bDescriptorType: 0x05 bEndpointAddress: 0x82 -> Direction: IN - EndpointID: 2 bmAttributes: 0x02 -> Bulk Transfer Type wMaxPacketSize: 0x0200 = 0x200 max bytes bInterval: 0x00 ===>Interface Descriptor<=== bLength: 0x09 bDescriptorType: 0x04 bInterfaceNumber: 0x02 bAlternateSetting: 0x00 bNumEndpoints: 0x00 bInterfaceClass: 0xFE -> This is an Application Specific USB Device Interface Class -> This is a Device Firmware Application Specific USB Device Interface Class bInterfaceSubClass: 0x01 bInterfaceProtocol: 0x01 iInterface: 0x05 English (United States) "DFU Interface" ===>HID Descriptor<=== bLength: 0x09



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bDescriptorType: 0x21 bcdHID: 0x000B bCountryCode: 0x20 bNumDescriptors: 0x00

4.2 Full-speed Configuration

The full-speed Configuration Descriptor is identical to the high-speed descriptor except the Video Streaming interface is removed.



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5 Testing

This section describes how to test the webcam on Windows. Two options are available:

An MM900EV2A module with a front facing OV9657 camera module.

Figure 5.1 MM900EV2A Module

An MM900EV2A module with a CleO camera module (OV5640). This has a modification (unseen) to the LDOs at U6 and U7 to support voltages of 1.2V and 2.8V for the camera module.

Figure 5.2 MM900EV2A Module with Cleo Camera Module

Each module was connected to and powered by a PC running Windows 7 or Windows 10.

To program the example code onto the FT900 device on the MM900EV2A board, refer to AN_325

FT90x Toolchain Installation Guide. The binary file name is “AN_414_FT90x_UVC_WebCam.bin” and it is found in the “Debug” directory.

5.1 VLC Media Player

The VLC media player uses Microsoft DirectShow to obtain video from the webcam. To connect to the FT90x webcam select “Open Capture Device…” from the Media menu. The menu item is shown in Figure 5.3.



http://brtchip.com/ft9xx-development-modules-landing/

http://brtchip.com/ft9xx-development-modules-landing/

http://brtchip.com/m-cleo/

http://brtchip.com/wp-content/uploads/Support/Documentation/Installation_Guides/ICs/MCU/AN_325_FT900_Tool_Chain_Installation_Guide.pdf


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Figure 5.3 VLC Media Menu

The Open Capture Device dialog has a drop-down box to select the device and an option for “Video Size” as shown in Figure 5.44. The device name of “FT900 UVC” is used by this application note.

In hi-speed mode any of the three supported resolutions can be used for the video size. If it is left blank then the highest resolution is used.

Valid options are “320x240” for QVGA, “640x480” for VGA and “800x600” for SVGA.



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Figure 5.4 VLC Open Capture Device Dialog

5.2 Skype

When the device is selected in Skype it will try to open at VGA resolution (640x480).

To test this select Tools --> Options --> Video settings.

5.3 Windows 10 Camera App

In Windows 10 there is a camera app that will support video from USB webcams.



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6 Performance

The following throughput results were obtained. These values are subject to verification and change.

USB hi-speed at VGA resolution: 7MB/sec.



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7 Importing into the FT90x Toolchain

The AN_414 Firmware found at the following link can be easily imported into the FT90x Toolchain:

http://www.ftdichip.com/Support/SoftwareExamples/FT90X/AN_414 FT90x_UVC_WebCam.zip

Once installed, select File --> Import --> General --> Existing Projects into Eclipse, and point to the downloaded and extracted project directory.

The project will appear in Eclipse Project Explorer as shown in Figure 7.1.

Figure 7.1 UVC WebCam Import

7.1 Changing the Application Software

The application software provided can be altered and changed if required. The FT90x Toolchain is a

free tool to enable code development and debug for the FT90x series and is based on plug-ins for the free popular IDE using the GCC compiler.

With each software change, the project should be rebuilt and reprogrammed into the FT90x IC. Please refer to AN_325 FT900 Toolchain Installation Guide for further information.



http://www.ftdichip.com/Firmware/FT90xToolchain.htm

http://www.ftdichip.com/Support/SoftwareExamples/FT90X/AN_414%20FT90x_UVC_WebCam.zip

http://www.ftdichip.com/Firmware/FT90xToolchain.htm

http://www.ftdichip.com/Support/Documents/AppNotes/AN_325_FT900_Tool_Chain_Installation_Guide.pdf

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23 Product Page


8 Contact Information

Head Quarters – Singapore Branch Office – Taipei, Taiwan

Bridgetek Pte Ltd 178 Paya Lebar Road, #07-03 Singapore 409030 Tel: +65 6547 4827 Fax: +65 6841 6071

Bridgetek Pte Ltd, Taiwan Branch 2 Floor, No. 516, Sec. 1, Nei Hu Road, Nei Hu District Taipei 114 Taiwan , R.O.C. Tel: +886 (2) 8797 5691 Fax: +886 (2) 8751 9737

E-mail (Sales) [email protected] E-mail (Sales) [email protected] E-mail (Support) [email protected] E-mail (Support) [email protected]

Branch Office - Glasgow, United Kingdom Branch Office – Vietnam

Bridgetek Pte. Ltd. Unit 1, 2 Seaward Place, Centurion Business Park Glasgow G41 1HH United Kingdom Tel: +44 (0) 141 429 2777 Fax: +44 (0) 141 429 2758

Bridgetek VietNam Company Limited Lutaco Tower Building, 5th Floor, 173A Nguyen Van Troi, Ward 11, Phu Nhuan District, Ho Chi Minh City, Vietnam Tel : 08 38453222 Fax : 08 38455222

E-mail (Sales) [email protected] E-mail (Sales) [email protected] E-mail (Support) [email protected] E-mail (Support) [email protected]

Web Site

http://brtchip.com/

Distributor and Sales Representatives

Please visit the Sales Network page of the Bridgetek Web site for the contact details of our distributor(s) and sales representative(s) in your country.

System and equipment manufacturers and designers are responsible to ensure that their systems, and any Bridgetek Pte

Limited (BRTChip) devices incorporated in their systems, meet all applicable safety, regulatory and system-level performance requirements. All application-related information in this document (including application descriptions, suggested Bridgetek

devices and other materials) is provided for reference only. While Bridgetek has taken care to assure it is accurate, this

information is subject to customer confirmation, and Bridgetek disclaims all liability for system designs and for any applications

assistance provided by Bridgetek. Use of Bridgetek devices in life support and/or safety applications is entirely at the user ’s

risk, and the user agrees to defend, indemnify and hold harmless Bridgetek from any and all damages, claims, suits or expense

resulting from such use. This document is subject to change without notice. No freedom to use patents or other intellectual

property rights is implied by the publication of this document. Neither the whole nor any part of the information contained in,

or the product described in this document, may be adapted or reproduced in any material or electronic form without the prior

written consent of the copyright holder. Bridgetek Pte Limited, 178 Paya Lebar Road, #07-03, Singapore 409030. Singapore

Registered Company Number: 201542387H.



mailto:[email protected]








http://brtchip.com/

http://brtchip.com/contact-us/

Application Note



24 Product Page


Appendix A – References

Document References

FT90x Datasheet: http://brtchip.com/m-ft9/

UMFT900EV2A Module Datasheet

tinyprintf http://www.sparetimelabs.com/tinyprintf/tinyprintf.php

AN_365 FT900 API Programmers Manual

AN_325 FT90x Toolchain Installation Guide

TN_158 What is The Camera Parallel Interface

DFU AN_380 FT900 Bootloader DFU Usage

TN_157 Ethernet Explained

USB and UVC specifications Revision 1.1 http://www.usb.org/developers/docs/devclass_docs/

Universal Serial Bus Device Class Definition for Video Devices

Universal Serial Bus Device Class Definition for Video Devices: Uncompressed Payload

FT90x Toolchain Download

AN_414 Firmware:


FT900 Software Examples: http://brtchip.com/ft90x/

Acronyms and Abbreviations

Terms Description

DFU Device Firmware Update

USB Universal Serial Bus

UVC USB Video Class

SCCB Serial Camera Control Bus

JPEG/JPG Joint Photographic Experts Group

VGA Video Graphics Array (640 x 480 resolution)

QVGA Quarter VGA (320 x 240 resolution)

SVGA Super VGA (800 x 600 resolution)

UART Universal Asynchronous Receiver and Transmitter (Serial Port)



http://brtchip.com/m-ft9/

http://brtchip.com/wp-content/uploads/2016/07/DS_MM900EVxA.pdf


http://www.sparetimelabs.com/tinyprintf/tinyprintf.php





http://brtchip.com/wp-content/uploads/Support/Documentation/Technical_Notes/ICs/MCU/TN_158_What_Is_The_Camera_Parallel_Interface.pdf

http://brtchip.com/wp-content/uploads/Support/Documentation/Technical_Notes/ICs/MCU/TN_158_What_Is_The_Camera_Parallel_Interface.pdf

http://brtchip.com/wp-content/uploads/Support/Documentation/Application_Notes/ICs/MCU/AN_380-FT900-Bootloader-DFU-Usage.pdf

http://brtchip.com/wp-content/uploads/Support/Documentation/Application_Notes/ICs/MCU/AN_380-FT900-Bootloader-DFU-Usage.pdf

http://brtchip.com/wp-content/uploads/Support/Documentation/Technical_Notes/ICs/MCU/TN_157_Ethernet_Explained.pdf

http://brtchip.com/wp-content/uploads/Support/Documentation/Technical_Notes/ICs/MCU/TN_157_Ethernet_Explained.pdf

http://www.usb.org/developers/docs/devclass_docs/

http://brtchip.com/ft90x-toolchain/

http://brtchip.com/ft90x-toolchain/


http://brtchip.com/ft90x/

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Appendix B – List of Tables & Figures

List of Tables

Table 2.1 Project Files Overview ........................................................................................... 5

List of Figures

Figure 3.1 Camera Interface Flowchart .................................................................................. 8

Figure 3.2 Main Control Flowchart ......................................................................................... 9

Figure 5.1 MM900EV2A Module ........................................................................................... 18

Figure 5.2 MM900EV2A Module with Cleo Camera Module ...................................................... 18

Figure 5.3 VLC Media Menu ................................................................................................ 19

Figure 5.4 VLC Open Capture Device Dialog ......................................................................... 20

Figure 7.1 UVC WebCam Import ......................................................................................... 22



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Appendix C – Revision History

Document Title: AN_414 FT90x UVC WebCam

Document Reference No.: BRT_000103

Clearance No.: BRT#061

Product Page: http://brtchip.com/m-ft9/

Document Feedback: Send Feedback

Revision Changes Date

1.0 Initial Release 2016-07-07

1.1

Updated Release

Dual branding to reflect the migration of the product to the Bridgetek name – logo changed, copyright changed, contact information changed

2017-02-17



http://brtchip.com/m-ft9/
